From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Mon, 29 Apr 2013 22:08:44 +0000 (-0700)
Subject: thp: fix huge zero page logic for page with pfn == 0
X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~128^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5918d10a4bb1081920a04e2c17197a02ff06e651;p=pandora-kernel.git

thp: fix huge zero page logic for page with pfn == 0

Current implementation of huge zero page uses pfn value 0 to indicate
that the page hasn't allocated yet.  It assumes that buddy page
allocator can't return page with pfn == 0.

Let's rework the code to store 'struct page *' of huge zero page, not
its pfn.  This way we can avoid the weak assumption.

[akpm@linux-foundation.org: fix sparse warning]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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